Current-limiting reactor



June 23, 1970 L. A MASTRJUKOV 3,517,354

GURRENTLIMITING REACTOR Filed July 28, 1967 FIG.

' INVENTOR LEV ALEXANDROVICH MASTRJUKOV United States Patent 015cc 3,517,364 CURRENT-LIMITING REACTOR Lev Alexandrovich Mastrjukov, 13 Parkovaya ulitsa 40/2 kv 36, Moscow, U.S.S.R. Filed July 28, 1967, Ser. No. 656,901 Int. Cl. H01f 27/30 U.S. Cl. 336-185 3 Claims ABSTRACT OF THE DISCLOSURE A current-limiting reactor having windings constituted by disc-type coils separated axially from each other by insulation spacers, each coil being wound of several parallel conductors, a part of the latter being constituted of a set of adjacent nonmagnetic steel strips.

The present invention relates to electrical reactors and, in particular, to current-limiting reactors designed for short-time duty.

Known reactors have windings made of single or several parallel conductors and are built up of disc-type coils separated from each other by insulation spacers.

A disadvantage of known designs is that in several cases, particularly under short-time duty conditions, the dynamic stability of the reactor becomes insufiicient and makes it necessary to employ a conductor of much greater section than is required according to the load-carrying capacity of the reactor.

A primary object of the present invention is to eliminate the above-mentioned disadvantage of the known reactors.

A further object of this invention is to provide a current-limiting reactor wherein the amount of conductor material to be employed does not depend on the specified level of dynamic stability of the reactor.

In accordance with the present invention, the above and other objects are attained by employing a set of nonmagnetic steel strips for making up a part of the above-mentioned parallel conductors.

All the parallel conductors of the coils may have a common insulation, alternatively, the set of steel conductors may have an insulation separate from that of the other parallel conductors.

The invention will further be described by way of example with reference to the accompanying drawing, wherein:

FIG. 1 is a side elevational view partly in cross-section of the reactor winding, in accordance with the present invention; and

FIGS. 2 and 3 are sections of two embodiments of the winding conductor.

It is apparent from FIG. 1 that the winding of the current-limiting reactor consists of disc-type coils 1 separated axially from each other by insulation spacers 2.

The short-circuit current flowing through the reactor applies an axial (compressing) force F and a radial (rupturing force F to the winding. An adequate mechanical resistance to the axial force that bends the 3,517,364 Patented June 23, 1970 winding turns can be provided easily by a proper selection of the number and width of the insulation spacers. The rupturing resistance of disc-type coils 1 is improved by winding two parallel rectangular conductors (see FIGS. 2 and 3) of which conductor 3 is made of copper or aluminum, whereas conductor 4 is made of steel and consists of a set of nonmagnetic strips for facilitating the process of winding. Each conductor is individually wound with a separate insulator 5 as shown in FIG. 3, or the conductors are combined and have a common insulator as shown in FIG. 2. After the process of winding has been completed, each disc-type coil 1 is bound securely, impregnated and all the turns are glued together reliably.

The radial forces will be applied to both conductors, irrespective of Whether the current is, or is not, passed through the steel conductor. Since the mechanical strength of the steel strip is several times greater than that of the copper or aluminum conductor, the tensile strength of the disc-type coil is sharplytincreased and the dynamic stability of the current-limiting reactor is greatly improved.

Due to the large contact area of the copper and steel conductors, the generated heat is transferred very quickly from one conductor to the other and the temperatures of both conductors will be approximately equal even at a very short duration of the flow of current. Consequently, the overall stability of the reactor is improved by the employment of strip steel.

The high economic efliciency of the present invention has been confirmed by use of the current-limiting reactor for breaking-capacity tests. A 6-fold reduction of copper has been attained as compared with reactors of the usual type. The overall dimensions and weight of the reactor have also been greatly reduced.

What is claimed is:

1. A current-limiting reactor comprising a winding constituted by individual disc-type coils axially separated from each other by insulation spacers, each coil being wound of two parallel coextensive conductors which are rectangular in cross-section, one of said parallel conductors being constituted of a high conductivity material, and the other conductor being constituted of a set of coextensive non-magnetic steel strips serving as a conductive material with high mechanical strength whereby to in crease the dynamic stability of the coils.

2. A current-limiting reactor according to claim 1, wherein all the parallel conductors of the coils have a common insulation.

3. A current-limiting reactor according to claim 1, wherein the set of steel strips is provided with an in sulation separate from that of the other parallel conductors.

References Cited UNITED STATES PATENTS 295,207 3/1884 Stone 174128 XR 1,331,077 2/1920 Moody 336-223 XR 2,419,591 4/1947 Quigley 174-128 THOMAS J. KOZMA, Primary Examiner U.S. Cl. X.R. 

